LDV CONVOY - ROOF LEAK - FIBREGLASS OR SEALANT?

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  • Hi there.


    I am the new owner of an LDV convoy minibus, will be doing the full works, restoration, seal, insulate, reflectives, cladding and pimping.


    So pulled all the plastics and seating out and now have seen some leaking coming down the side walls, right down to the rear light, little scary but hopefully I can get this sealed before any damage is done!


    It has to be from where the plastic roof meeta the metal, I do seem to remember a small 2mm to 3mm gap running along the gutter area but assumed this was normal..


    Anyway what would be the best methid here, some sort of silicone sealant or fibreglass? I assume something with flex as there will probably be a lot of flex up there? What about Skilaflex?


    Hopefully this has not been asked too much and we can all benefit from it, I did search this forum but found nothing on this.


    Thanks.

  • Convoys always leak..mine does and has done since 2 years old.Usually they leak around the front windscreen and below the front scuttle by the windscreen wiper spindles and onto the front floor and because the flooring is foam it absorbs water and rots the floor.The roof leaks are not so common but its because it flexes a lot so you want some flexible sealant.Fibreglass will fill the hole but wont be flexible enough to seal.I just use silicone sealant or sikaflex512 which is caravan and motorhome flexible sealer.If you repaint the guttering channel afterwards it should seal it.Check first that there are no rust pinholes in the guttering,particularly any panel seams as Convoys tend to rot there quite quickly.
    As mentioned before re the rubber/foam cab flooring,get rid of it and replace with closed cell insulation once youve checked theres no sign of water ingress.Not many Convoys are dry in the cab area and the floor matting is the major cause of rot in the floor and footwells.

  • Thanks!


    Good shout on the foam flooe in the drivers cab, yes I noticed that was wet...


    Would skilaflex be good for the roof/van seal then fibreglass over it? Or what other sealant? Also use a wirewheel on drill to clean out the current roof/van seal? Any othr prep before I use seal?

  • The floor mat holds literally gallons of water when soaked and if you park on a camberso one side of the vehicle is higher youll see water dripping.from the footwell for days.You can buy closed cell vehicle insulation of various thicknesses quite cheaply on ebay.Then you can fit a hard rubber floor on top or carpet.Before you do though its worth exploring where the leak is.You can get new.windscreen sesls as the old ones were prone to split but youll need to get a windscreen expert to.deal with it unless you know what youre doing.Theyre not the easiest screens to deal with.


    As for the roof if youhave a wide gap you should check the bolts securing the roof.They may need tightening or may have rusted through the gutter.If its just one area youll probably get away with filling the hole with sealer and tightening down the roof but be careful not to over stress it or the fibreglass will crack.
    If its not a major gap you can fill with sealant from a tube.you can buy mastic sealant in tape form used on caravan and motorhomes for sealing roofs roof vents and windows etc but using that youd have to lift the roof to apply the tape then rebolt it down and thsts not a simple job.
    Using sikaflex on.its own should be ok and if you just paint over it you can keep a check on it and reseal if required.If you glass over it youll make.it harder to.deal with in the future if you have to.I either use sikaflex or coloured silicone vehicle screen sealer.You best cleaning any old sealer out and loose paint or rust or you wont have an effective seal.


    Iknow someone doning(not me)whos done an effective job painting the gutters regularly with rubber roof sealant but its mot the most aesthetically pleasing look :) but it works.


    While youre at it check the sills and especially the rear body behind the rear wheels and across the back behind the rear number plate because thats usually where convoys tend to rot away most..mine has,which ive got to get fixed this year for MOT

  • 3mm :eek:
    Wire wheel is a fair option. Then some rust treatment. Then some paintable sealant as already mentioned.
    We bought a scrapper and it has lead flashing all round the roof!!! :D


    Bit of a gap yes...id say someones possibly hit a barrier ....mines ex post office and still has obvious signs of having been dragged under a low roof or barrier and thats usually what disturbs the roof seal,fortunately mine only leaks by the front door pillar...though as you know not many LDV are ever totally waterproof.

  • I wa prob a bit ott on the 3mm gap, maybe a lot less, this damn rain not letting me get out.


    I took the fan cover off last night and now today it's leaking through the fan vent thing!! Bought some sealant that works under water and smothered the entire area but not seemd to work, maybe a little. This common?

  • LDV - leaky damp van.....


    There are loads of places they leak, some already mentioned..


    Windscreen seal, wiper spindles, gutters, sticker above ecu on firewall, door seals, windows, gutter under scuttle under bonnet if rotten, all are fixable bit youll need to work round them. Pop over to the ldv facebook page and ask on there for a full list of likely leaks.


    https://m.facebook.com/groups/274279322725138/


    Sikaflex ebt will seal most holes, is flexible, waterproof and cheap.

  • I wa prob a bit ott on the 3mm gap, maybe a lot less, this damn rain not letting me get out.


    I took the fan cover off last night and now today it's leaking through the fan vent thing!! Bought some sealant that works under water and smothered the entire area but not seemd to work, maybe a little. This common?


    Which fan? Roof vents almost always leak on ldv....i dont have any.If youre on about the cab.heater,yes they leak there too.You just meed to go.around tackling them.ome by one.Ypu need to apply sealer to dry clean surface or it wont seal.properly.
    The problem with most vans when holes cut in them theres a source for leaks but ldv seem to have excelled in this area...Im glad they never made boats or submarine.

  • Well learned a lot tonight. Ripped the entire front cab floor covering up with its 2 inches of foam, must have been about 4 liters of water soaked up in the foam! Crazy, felt so good to get it up, also explored the entire roof where it joins the main body and it has to be at the front, the water is seeping down the window frame through the body and being held in that foam, most likely draining out through the factory holes in the floor, allowing more to come in when it rains. If I lived in Spain this would not be a problem!!

  • When its dry get an assistant to run a hose over the van. Start low down and slowly go up until you see water coming in. Sort leak and repeat until no more.
    If you start at the top you'll have no idea where it it as it could run down, or take a bit of time to work through.

  • It's worth mentioning that the best way to seal leaks is from the outside, otherwise you just end up with water trapped in inaccessible places. High modulus silicone is great as long as you clean the surfaces really well, Sikaflex is excellent too, when I worked in a boatyard we used it to fix Perspex windows into GRP boats. Note that Perspex has a high expansion rate, so limit the size of windows, build in expansion capability or make them in sections. This goes for any vehicle made from dissimilar materials, a strong bond isn't going to help if one section expands to 5mm longer than the other when the Sun shines.

  • I used to have the same problem with an old landrover.The floor was always sopping wet from leaking screen so i drilled a couple of holes in the floor,cleaned it thoroughly and painted it in fibreglass resin gelcoat.End of water problem and no rust.


    The water on front Convoy floor does not normally get further back than the front seats as theres a box channel ridge behind the seats.Youll probably find the floor at the back dry unless water is travelling along the metal channel the roof is attached to or coming in through side windows or the frames or from above the side loading door as the seal is usually pretty useless.
    Any water ingress usually drains down the inside of the panels to the sills.Treat it all with waxoyl before you start boxing it all in.Make sure all the drain holes in sills doors and chassis members are clear and spray them inside with waxoyl and if youre in the mood, paint with tekaloid enamel paint,its used on tractors and rust inhibiting.
    You should be able to keep the tinmice at bay for quite some time but ive done all that and still have rust.


    Tackling the leaks is essential though as it doesnt take five minutes in the right conditions to open the van up and find mildew everywhere,not something you want especially when living in it.


    You can get closed cell car/van insulation on ebay in various lengths and thicknesses like this ebay item number 252376922269 pretty cheap.

  • Thanks all for info.


    The foam matting in the front cab has completely gone now, I will be sound proofing and insulating that in due time, main thing now is to get that roof sealed as well as the fan vent.


    2 questions.


    Fan vent: I looked on top from standing near the rear door, and the only thing I can think is that it is sealed with silicone and the seal has broken? There is a ridge and I guess this pops up from the van, and the fan is held in place by a sealant?? It looks like I need a totaly new extractor fan, do most people just get rid of these and install a new one? It needs sorting.


    Roof seal: Check pic below, this is the back of the van drivers side where roof meets van. Some people say this is too far out and not deep enough?


    ukhippy.com/attachment/26267/


    It is not as bad as this all the way round though, mainly at the rear and the front.


    Do I use sikaflex on this and scrape old sealant out, or fibreglass it? Also is an idea to loosen roof bolts and pull roof down and tighten?


    The floor in the cab after pulling all the foam flooring out is not that bad considering.

  • The roof lip should sit in the gutter but i doubt theres much you can.do about it without lifting the roof and removing all the sealer and possibly cause leaks elsewhere.POssibly someones tried reseating the roof before hence its odd seating..As Rick said,get as much of the sealer out and reseal.Sikaflex 512 is caravan/motorhome sealer for most applications. 291 is marine but 512 should be fine.Its what ive used on my trailer windows.


    The vent should be held in place with a flange plate inside sandwiching the roof between. the.outside vent body and flange with either a solid rubber or silicone sealer on the oitside.
    Personally id measure the hole diameter from inside and get a new roof vent kit of the same size.Either one of the wind driven rotary vent or a solar driven one like some motorhomes have..either will help keep the air moving in the van and reduce condendation...if fitted properly it shouldnt leak.
    Fitting roof skylights on hi roof LDVs is not really an option as most of the roof is ribbed and difficult to seal a large skylight so youre stuck with small vent option.
    If youre planning to have a woodburner in the van you should think about that position too and plan your build accordingly.If not it wont matter so much.


  • The vent should be held in place with a flange plate inside sandwiching the roof between. the.outside vent body and flange with either a solid rubber or silicone sealer on the oitside.
    Personally id measure the hole diameter from inside and get a new roof vent kit of the same size.Either one of the wind driven rotary vent or a solar driven one like some motorhomes have..either will help keep the air moving in the van and reduce condendation...if fitted properly it shouldnt leak.


    Damn this sounds technical. So not just a case of scraping old sealant out and squeezing new stuff in. I don't want to totally mess my van up by lifting the roof off. :/


    Could I just scrape out the existing, unbolt roof bolts and pull down, maybe lift about 5mm and scrape what I can and squeeze sika under the roof and lower, then squuze sika all around sides and top of roof / van meet?

  • Personally I wouldn't disturb the roof. I would make sure it's very clean, wire brush the metal and treat any rust you find and paint. Clean the fibreglass with a bleach kitchen spray. Don't worry about the paint.
    Then reseal. Paint again, maybe do the whole van. Rollering a whole van can be done in a weekend if you don't change the colour.

  • Thank you all for info, I am feeling excited to give this a go, and yes I will not lift the roof, I will just undo the bolts and let the weight of itself drag it down after I have cleared all the old sealant out. I'll wack some SIKA 512 in there and as much as possible under the window rubber.


    Would it be an idea to use this SIKA in other places also? Like for exampe I noticed yesterday that the rear wheel arch is riveted on, and there technically is at least an air gap there, would it be an idea to seal this from inside the van? And other possible holes or are these essential at least for some air ventilation? I keep reading how air circulation is important.


    Thanks again for all your help, I'll be a pro by the end.


    (also any idea on roughly how many tubs of sika 512 I should be aiming to use on the roof seal? Both sides?)


  • The vent should be held in place with a flange plate inside sandwiching the roof between. the.outside vent body and flange with either a solid rubber or silicone sealer on the oitside.
    Personally id measure the hole diameter from inside and get a new roof vent kit of the same size.Either one of the wind driven rotary vent or a solar driven one like some motorhomes have..either will help keep the air moving in the van and reduce condendation...if fitted properly it shouldnt leak.


    Hi mate, what's this flange about? And roof vent?


    Looks like there are palces where the roof is fluch to the metal without sealant? I will get pics to you on here asap.

  • Hey here are some pics of what I meant. So would you suggest using sikaflex on top and underneath van?




    Plus there are holes from where the seats are, best method to fill these in?


    Also a piss poor effort by previous owner on this, would sikaflex also be the best product here, sand it all back?



    Not sure how I did not spot any of this before I bought the van!

  • You aren't mistaking the spot welds for pop rivet heads are you?
    I wouldn't bother sealing every little bit, by the time you insulate and clad it you wont feel any draught and a little bit of ventilation will allow any moisture behind there to escape.


    You'll also probably end up drilling big holes for ventilation of one form or another anyway so airtight isn't really worth striving for.


    Holes in floor from seats? Are these minibus seats that you have removed? If so just put the bolts back in the holes and batten/insulate over them.

  • Hi mate, what's this flange about? And roof vent?


    Looks like there are palces where the roof is fluch to the metal without sealant? I will get pics to you on here asap.


    Basically you should have a vent that is in two halves.A piece that fits on top of the roof with a seal and a piece that fits inside and the two halves are bolted together through the roof material so forming a tight mounting and watertight seal.




    As for the photos youve posted it doesnt actually look too bad. Clean all the rust off with a wire brush.If theres any big holes that shouldnt be there get them welded.Otherwise just paint with some decent rust inhibitor paint like tractol or tekaloid.Spray spme waxoyl around the lower panels and then you can get on with the build.


    Dont bother with sikaflex underneath the vehicle,theres no need.Just rust proof as much as possible with waxoyl.


    Main thing is Seal the roof properly.


    Id check out the joint in your third pic in case it actually needs welding as its structural member but if its ok just rustproof and refill it with body filler and paint it.If you take off the plastic trim panel that runs up that side of the widscreen. Inside ,you will be able to see if theres any serious rust in that joint.


    LDV's alll go a bit manky along panel joints,ithey were never painted that well....ts just best to clean them back,treat the rust and repaint.

  • Just a quick question :angel:.


    This is lined on the roof, obviously it will have some sound and warmth insulation properties? It's some kind of coarse carpet.


    I was originally going to use foil bubble wrap to spray on roof (which is the fibreglass from hitop convoy), would I be best leaving this on and putting the foil over it or taking it off and leaving off?